We propose to generate human monoclonal antibodies to cell surface receptors of known functional importance by immunizing normal human peripheral blood cells in vitro under serum-free culture conditions. These antibodies will be examined for their effects on the growth of human tumor cells bearing the appropriate receptors. The methodologies that will be developed will significantly reduce the current problems involved in obtaining suitably immunized human lymphocytes and will make human monoclonal antibodies with useful specificities more accessible to the scientific community.